Coat the pork with olive oil and sprinkle with salt and pepper. Arrange the parsley and sage leaves along the top of the roast.
Lay the bacon horizontally in a roasting pan, with the strips touching. Set the pork roast in the center of the pan and fold the bacon over to wrap the roast.
Add the potatoes and onions to the pan, to border the roast. Transfer to the oven and roast until the bacon is crisp and the pork reaches an internal temperature of 140 degrees F on an instant-read thermometer, about 1 1/2 hours.
Transfer the roast to a cutting board and rest for 10 to 15 minutes. Slice and serve with the potatoes and onions.